zimbra.cogeco.net has no MX records.
Question and response
Question
dig zimbra.cogeco.net. MX
Answer
The response has no answer records.
Authority
zimbra.cogeco.net. 86400 SOA ns1.cgocable.net. dnsadmin.cogeco.ca. 5 1800 900 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0